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Final Drainage Report, May 29, 2015 <br />Canyon Dolomite Old Quarry Project <br />Project should have no impact on flows at upstream or downstream sites. <br />C. Tables, Charts, Figures, and Drawings <br />This drainage report includes the following tables, charts, figures, and drawings: <br />• Drainage Basin Map <br />• Soil Survey information <br />• Basin area, % impervious, and Time of Concentration calculations <br />• Rainfall from NOAA Atlas <br />• Runoff by Rational Method <br />• Approach channel flow calculations by Manning Equation <br />• Rock chute calculations using methods by KM. Robinson <br />All calculations are in conformance with the design criteria presented above. <br />B. Summary of Results <br />Hydrology Results <br />Flows for the 10 year 100 -year storms were calculated using the Rational Method. The <br />10 -year flow is estimated at 29.6 cubic feet per second (cfs) and the 100 -year flow is <br />estimated at 98.7 cfs. <br />modeled using HEC -HMS. Flows for the 10 -year and 100 year storms were also <br />calculated using the Rational Method as a basis of comparison. The HEC -HMS flows are <br />considered to be more accurate because HEC -HMS is a more appropriate method to use <br />for a basin the size of Gilson Gulch. <br />Hydraulics Results <br />The approach channel shall be trapezoidal, with bottom width 6 feet, side slopes 3:1, and <br />two feet deep. <br />The rock chute has a slope from ranging from approximately 15% to 25%. To be <br />conservative, it was assumed that the entire chute is 25% slope. See the calculation sheets <br />for the configuration of the rock chute. <br />VI. CONCLUSIONS <br />The calculations and design elements presented here are designed to safely pass the 100 - <br />year storm flows through the Canyon Dolomite Old Quarry Site. <br />Canyon Dolomite-Draune Report May2015-rev0 doc Page 3 <br />